The first three games follow Professor Hershel Layton and Luke Triton's adventures together. The subsequent three games and the film are prequels, and focus on how Luke and Layton met, and their "original" adventures. Each title is based in a series of puzzles and mysteries given by the citizens of towns that the main characters visit. It is not necessary to solve all the puzzles to progress, but some are mandatory, and at certain points in the game a minimum number of puzzles must be solved before the story can continue.

Lifetime cumulative sales of Professor Layton games are at 10 million units sold as of October 2010.[2] As of April 2015, the series has sold over 15.5 million copies.

The main character in the Professor Layton games is Professor Hershel Layton, a renowned archaeologist and a well-mannered gentleman. He is called to solve various mysteries in different places. Professor Layton is always accompanied by his apprentice Luke Triton, a cheerful and curious boy who brings a touch of humor to the story of Layton. According to Hino, Layton is partly inspired by the character of Phoenix Wright of the Ace Attorney series. Wanting to improve over what he saw as "bad points" in Phoenix's character, he was able to develop Professor Layton.[4]

There was also a "Friendly Version" for The Curious Village, from which all weekly puzzles are unlocked, as well as the game being slightly easier for those who were troubled previously. For Diabolical Box, the Japan-only "Level-5 Premium Silver/Gold" collections on Nintendo DS included an exclusive side-story, "Professor Layton and the London Holiday" (レイトン教授とロンドンの休日?) in addition to the actual game and another Level-5 game, Inazuma Eleven. The Holiday in London includes ten puzzles, some of which are from the first game, and a short storyline, set in Professor Layton's London office, in which he reminisces about his previous adventures around the world.

The puzzle interface for the Professor Layton series allows the player to work out the teaser on the touchscreen (bottom) part of the DS display while following the instructions given on the top screen. This puzzle is from Professor Layton and the Unwound Future.

The game is essentially a collection of puzzles with exploration sections between them. The player (as Professor Layton, Luke and other characters) explore their environments in a point-and-click adventure game fashion using the DS's touchscreen. This can be used to talk with non-player characters, learn more about the environment, moving between different areas, or to find hint coins that are used during puzzles. Often, when interacting with a person or object, the player will be presented with a puzzle, valued at a number of "picarats", a type of currency within the game. Solving the puzzle correctly will earn the player that many picarats, but a wrong answer will reduce the value a small amount on subsequent attempts down to a minimal picarat number. In order to progress the plot, the player is required to solve specific puzzles, or to solve a minimum number of puzzles or gain a minimum amount of picarats. When the player leaves an area due to progression of the plot, puzzles they have yet to find or solve are collected and placed into a "Puzzle Shack" owned by a fictional character known as "Granny Riddleton", where they can return and attempt to resolve later. The Curious Village contains 135 puzzles, The Diabolical Box contains 153 puzzles, The Unwound Future contains 168 (The later two having another special puzzle obtained via the use of codes found in the previous game), The Last Specter contains 170, The Miracle Mask contains 150, and The Azran Legacy contains 165.

The puzzles take the form of brain teasers and are only loosely tied to the plot. All puzzles were created for this series by Akira Tago, who is famous for his best-selling Mental Gymnastics series. They take the forms of math problems, logic puzzles, mazes, sliding-block puzzles, and brain teasers. The games give the player the opportunity to bring up a translucent memo screen they can write on using the stylus to work out their answer before submission. If the player is stuck, they may spend one hint coin to receive a hint. Each puzzle has three hints available, and within The Unwound Future, the game introduces "super hints" that nearly solve the puzzle for the player but which can only be bought with two hint coins and after the three other hints have been revealed. The puzzles are not timed, though for puzzles such as mazes or sliding blocks, the player may be challenged to complete the puzzle in a limited number of moves.

Each game features an additional set of three unique meta-puzzles that can be accessed at any time through "Layton's Trunk". These puzzles generally require the player to complete specific puzzles in the game to receive items to use within the meta puzzle; for example, The Curious Village gives the player furniture as a reward for some puzzles, which then must be placed within a set of apartments to Layton's and Luke's exacting desires in the meta puzzle; the meta puzzle cannot be solved completely until all the furniture has been collected. Completing the game also opens a number of series of more difficult puzzles to be solved, including one that involves a curiously heavily-locked door that the player may encounter during the game. Until its cancellation in 2014, the games could use the DS Nintendo Wi-Fi Connection features to connect to Nintendo world network and unlock additional puzzles for play for a number of weeks after each game's release.

Professor Hershel Layton(エルシャール・レイトン,Erushāru Reiton?) is the title character and protagonist of the series. He is a stereotypical Englishgentleman, who enjoys solving puzzles and drinking tea. He is a professor of archeology at London's Gressenheller University. Because of his prowess at solving puzzles and mysteries, he is well known throughout London. His catchphrase is, "That's what a gentleman does." The signature feature of his appearance is his black top hat (given to him by his deceased sweetheart, Claire), which he wears along with an orange shirt under a black high-collared coat with matching pants. As he became a professor at age 27, he is 37 in the first trilogy.[7] Layton is voiced by Yo Oizumi in Japanese and Christopher Robin Miller in English.[8][9]

Luke Triton(ルーク・トライトン,Rūku Toraiton?) is a young boy who accompanies Professor Layton. He aspires to be a gentleman like his professor, though, like many boys his age, he has a tendency to let a cheeky remark slip out. He is fond of puzzles, animals, teddy bears, and the color blue. Luke is also able to understand and converse with animals and has an appetite he can never seem to quench. While he consistently wears a sweater throughout the first trilogy, he wears suspenders in The Last Specter and The Eternal Diva, a vest in The Miracle Mask, and an open coat in The Azran Legacy. Layton is an old friend of Luke's father, Clark.[7] Luke is voiced by Maki Horikita in Japanese, Lani Minella in US English and Maria Darling in UK English.[10][11]

Flora Reinhold(アロマ・ラインフォード,Aroma Rainfōdo?, Aroma Reinford in Japanese version) is the daughter of the wealthy Augustus Reinhold and his wife, Viola (both of whom died before the events of The Curious Village). After the events of The Curious Village, she becomes Layton's protégée and joins Layton and Luke on their mysteries. She also loves to cook, but, to Layton and Luke's dismay, she cannot cook well.[12] Flora is voiced by Mamiko Noto in Japanese and Lani Minella in English. Claire Morgan voices her in The Eternal Diva.[13]

Emmeline "Emmy" Altava(レミ・アルタワ,Remi Arutawa?, Remi Altava in Japanese version) is Professor Layton's assistant as appointed by the President of Gressenheller University and one of the main characters of the second trilogy. She loves taking pictures, taking her camera everywhere, and demonstrates impressive martial arts skills. Emmy is voiced by Saki Aibu in Japanese and Lani Minella in English. Emma Tate voices her in The Eternal Diva.[14]

Inspector Chelmey(チェルミー警部,Cherumī Keibu?) is a shrewd detective with London's Scotland Yard, reputable for striking fear into the hearts of London criminals, even though that fear seems to be misplaced. Despite this, it seems that Layton and Luke always manage to be one step ahead of the inspector. When not working, he enjoys his wife's sweet potato fritters. In the European releases of the games, his favourite food is cakes.[12] Chelmey's assistant, Constable Barton, is a timid man prone to making mistakes, though he has covered up for some of Chelmey's oversights in the past.[12] Chelmey is voiced by Shiro Saito in Japanese and Christopher Robin Miller in English. Jonathan Keeble voices him in Eternal Diva.[15]

Don Paolo(ドン・ポール,Don Pōru?), Layton's self-declared nemesis and the main villain of the first game (he has a minor role in Diabolical Box and allies with Layton in The Unwound Future), is a brilliant scientist and inventor banished from the scientific community for performing unethical experiments. A genius of machinery and a master of disguises, Don Paolo studied in the same university as Layton, and his unrequited love for Layton's deceased girlfriend Claire Foley caused his hatred for the professor. When he is not plotting evil, Don Paolo enjoys making and listening to music. Paolo is voiced by Minoru Inaba in Japanese and Christopher Robin Miller in English. Jonathan Keeble voices him in The Eternal Diva.[16]

Inspector Clamp Grosky(クランプ・グロスキー,Kuranpu Gurosukī?) is a police inspector from Scotland Yard who plays a role in the second trilogy similar to Inspector Chelmey's in the first. He has a younger sister named Amelie who goes on to marry Chelmey, making Chelmey Grosky's brother-in-law. The energetic Grosky has a fiery passion for mysteries that require his expertise and is also very athletic, apparently able to run faster than cars and swim faster than sharks. His distinguishing features are his chest hair and his pompadour hairstyle.[17] Grosky is voiced by Houchu Ohtsuka in Japanese and Stuart Organ in English.[18]

Jean Descole(ジャン・デスコール,Jan Desukōru?), a masked scientist and archaeologist, is one of the main antagonists of the second trilogy in the main series as well as The Eternal Diva. In each of his appearances, he competes against Layton, as well as a crooked archaeology organization called the Targent, in search of historic sites connected to the ancient civilization of the Azran. Like Don Paolo, he is also a master of disguise and even spends most of The Azran Legacy hiding as peaceable archaeologist Desmond Sycamore (Simon Foster in the UK) to deceive Layton. He is secretly Layton’s long-lost older brother, who gave him the name Hershel when the brothers were given up for adoption after their father was abducted by the Targent. Descole is voiced by Atsuro Watabe in Japanese and Walter Rego in English. Jonathan Keeble voices him in The Eternal Diva.

Granny Riddleton(ナゾーバ,Nazōba?) is a recurring character, first appearing chronologically (though not present for the rest of the game) in The Last Specter. Most characters view her as a witch, presumably due to her pointed hat and distinctive laugh. She gathers all the puzzles players could potentially miss as they progress through the games, storing them in a small hut to solve later.[19] In The Unwound Future, she retires and is soon succeeded by her granddaughter, Puzzlette(ナゾリーヌ,Nazorīnu?), who swats a substitute guard and talking bee named Beasley upon her succession. Riddleton's pet cat, Keats, appears in the prequels except for The Miracle Mask, wherein she appears disguised as "Nana Grams" (a portmanteau of "nana" and "anagrams")/"Elizabeth" with thick eyeglasses.[20][21]

The only games and media with overarching structure are TheLast Specter, The Eternal Diva, The Miracle Mask and TheAzran Legacy. Other games and media in the Professor Layton series do not have any overarching structure or direct connection to each other, but do follow a chronological order through the appearance of reoccurring characters met in earlier works.

Professor Layton and the Curious Village: The first game in the series, released for the Nintendo DS in Japan during 2007 and localized elsewhere during 2008. Layton and his young apprentice Luke are invited to the town of St. Mystere by the family of late Baron Augustus Reinhold to figure out the secret behind his last will and testament, in which he stated that anyone who found the Golden Apple hidden within the town would be entitled to his entire fortune. Upon entering the town, it is clear to both of them that the curious village holds many more secrets than they had expected. They solve their way through 138 puzzles to discover the truth behind St. Mystere.

Professor Layton and the Diabolical Box: The second game in the series, released for the Nintendo DS in Japan during 2007 and localized elsewhere during 2009. It is known in PAL regions as Professor Layton and Pandora's Box. It begins with the Professor and Luke traveling to meet Layton's mentor, Dr. Schrader, who has sent the pair a letter detailing his procuring of the Elysian Box, a chest rumored to kill anyone who tried to open it. Upon walking into his apartment, he is found lying on the floor, dead, with the box missing. The only clue he left behind was a train ticket for the high-class Molentary Express without a mentioned destination, which they promptly catch to begin their investigation to find out more on the fate of Dr. Schrader, and the whereabouts of his diabolical box. During their search, they encounter 153 additional puzzles.

Professor Layton and the Unwound Future: The third game in the series, released for the Nintendo DS in Japan during 2008 and localized elsewhere during 2010. It is known in PAL regions as Professor Layton and the Lost Future. The game starts upon Luke receiving a letter purportedly sent by himself, ten years into the future, only a week after an accident in which Dr. Stahngun's failed demonstration of a time machine caused himself and the Prime Minister to vanish. He and Layton travel to a desolate part of town to investigate a clock shop, but upon walking out, find themselves to have been thrust forward into the future London, ten years from then. In their efforts to find the truth of their unwound future, they are forced to solve 168 new puzzles, and to remember a forgotten past. This game is currently the last in the series chronologically.

Professor Layton and the Last Specter: The fourth game in the series was released for the Nintendo DS in Japan during 2009 and North America on October 17, 2011. It is known in Europe as Professor Layton and the Spectre's Call. It is, chronologically, the first game in the series, in which Layton is called by an old friend named Clark to the mysterious, dark, and foggy town of Misthallery, where legends exist of a great, shadowy giant who protects the region whenever a special flute is played to summon him. However, recently, the figure has turned against the village, and it is up to the Professor, a young boy of the village named Luke Triton who is heavily involved in the legend of the Specter, and Layton's new assistant Emmy Altava, to figure out why the specter is wreaking havoc in the town. Together, they investigate the village and the Last Specter, and, while doing so, solve another 170 puzzles. In the USA and Japan, the game also includes an RPG called London Life, which was co-developed by Brownie Brown. It was excluded from the EU version due to 'time constraints'.

Professor Layton and the Miracle Mask: The fifth game in the series, released as a launch title for the Nintendo 3DS on February 26, 2011 in Japan, releasing in the UK on the 26 October 2012, and in North America on the 28 October 2012. Professor Layton, Luke, and Emmy travel to a place known as Monte d'Or in search of a powerful mask said to have created the city. Professor Layton is forced to recall his past in order to uncover the secret of the mask in the present. The truth is hidden deep within the Miracle Mask. Level-5 claims that the game will have daily puzzles available for download over Nintendo Network via SpotPass for a full year.[22]

Professor Layton and the Azran Legacy: Level-5 confirmed a 6th and final game for the second trilogy taking place after The Miracle Mask and the second film chronologically.[23] In a Nintendo Direct presentation on August 29, 2012, the title was revealed to be Professor Layton and the Azran Legacy for the Nintendo 3DS and, according to Level 5 CEO Akihiro Hino, is the last Layton title to star Layton himself as the protagonist. It was released in Japan on February 28, 2013, Europe on November 8, 2013, and North America on February 28, 2014.[24][25]

Layton Brothers: Mystery Room: An iOS/Android video game, Layton Brothers: Mystery Room(レイトンブラザーズ・ミステリールーム,Reiton Burazāzu Misuterī Rūmu?), was released on September 21, 2012 with the main protagonists being Lucy Baker and Alfendi Layton, son of Professor Layton. This is Level-5's first iOS game.[27]

Professor Layton vs. Phoenix Wright: Ace Attorney: Announced on October 19, 2010 at Level-5's annual vision event, this game is a cooperative project between Level-5 and Capcom, and a crossover between the Professor Layton and Ace Attorney series. In it, Professor Layton, Luke, Phoenix Wright, and Maya Fey, find themselves in a medieval world separate from their own, known as Labyrinthia. This world is controlled by a man known as the Storyteller, who can make anything he writes down a reality. The land also speaks tales of witches, who hide in the shadows. It was released in Japan for the Nintendo 3DS on 29 November 2012, in Europe on 28 March 2014, a day later in Australia and in North America on the 29 August 2014.

Another game, titled Layton 7(レイトンセブン,Reiton Sebun?), has been announced for iOS, Android and Nintendo 3DS, sporting a rather different style from its predecessors. The "7" in the title refers to the number of the playable characters (including a zombie, a taxi driver, and a dog[28][29][30]) rather than the number of the installment. Professor Layton himself also makes an appearance in the game.

Level 5 CEO Akihiro Hino confirmed during a livestream in June 2016 that a new entry in the series which he described as legitimate will be shown at the Level 5 Vision 2016. It has been also been confirmed that neither Professor Layton, nor his son Alfendi, is the title character in the game.[31]

Lady Layton: The Millionaire Ariadone's Conspiracy is an upcoming puzzle video game in development by Level-5 for Nintendo 3DS, iOS, and Android. The game is the seventh main entry in the Professor Layton series and follows a new protagonist, Katrielle Layton, who searches for her missing father Professor Hershel Layton. The game is planned to be released in 2017.

Humour manga intended for child audiences was first serialized in February 2008 in the special edition of Bessatsu CoroCoro Comic. The series has since ended. The title of this manga is Professor Layton and the Cheerful Mystery(レイトン教授とユカイな事件,Reiton-kyōju to yukai na jiken?), covering many mysteries in the story. Several chapters are based on the games; most of the others are original stories with little relation to the game canon. The chapters also included puzzles for the readers to solve. The series was collected into four volumes, with the final volumes coming out in June 2012. Tokyopop has released all four volumes in German under the name Professor Layton und seine lustigen Fälle. The series has also been released in Spanish under the name El Professor Layton y sus Divertidos Misterios by Norma Editorial, in French as Professeur Layton et l'étrange enquête by Kazé Manga and in Italian as Il professor Layton e i misteri buffi by Planet Manga.

An animation film called Professor Layton and the Eternal Diva was produced by Masakazu Kubo, who is mainly known for producing the Pokémon films, and animated by P.A.Works, the same company that develops the animated cutscenes for the games. It contains an original story, separate from the game series,[6] and taking place after the events of The Last Specter. It has been a general success in both Japan and Singapore where the movie was released. The film was released in the United Kingdom on DVD and Blu-ray Disc by Manga Entertainment on October 18, 2010. Viz Media announced they had licensed the movie at the 2011 Anime Expo and released it on DVD in North America on November 8, 2011 A sequel is being made as well as a live action feature.[33]

Three books based on the Professor Layton series were also made, though they are still in Japan only. They consist of Professor Layton and the Wandering Castle in 2008, Professor Layton and the Phantom Deity in 2009, and Professor Layton and the Illusory Forest in 2010.

The Professor Layton series has been generally successful in the UK, the US, and Japan. Professor Layton and the Curious Village sold over 700,000 units in Japan in 2007.[48] The game was also the top selling game for the Nintendo DS in the United States in the first three weeks after its release. After it was restocked in the UK, sales of Professor Layton increased 54%, moving it from 10th place to fourth place.

Curious Village received generally positive reviews from critics. On the review aggregator Game Rankings, the game had an average score of 86% based on 48 reviews. On Metacritic, the game had an average score of 85/100, based on 57 reviews. The combination of the adventure game and "brain training" genres received mixed appreciation. Some reviewers praised the game for the successful combination with 1UP commenting on how the game's approach is much better than games where the puzzles were integrated into the environment. Other reviewers felt that these two genres do not merge well within the game; Game Informer noted that while the player is given numerous small puzzles to solve, the mysteries of the main plot are basically solved for the player. The game was noted to have little replay value; once all the puzzles were solved, there was no point in playing through them again. The presentation of the game, including both the general European animation style and cutscene animations, was appreciated by reviewers. Hyper's Darren Wells commends the game for its "clever concept, with plenty to solve and unlock as well as its fantastic presentation". However, he criticizes "some puzzles feeling tacked on and the music can get annoying".

Professor Layton and the Diabolical Box was considered to be a major improvement from the original. In Japan, the game has sold 815,369 copies, according to Famitsu, as of July 9, 2008.[49] The UK's Official Nintendo Magazine awarded the game a score of 92% (and consequently their Gold Award medal), praising the increased number of puzzles, animated scenes and voice acting, but complained that it could be slightly repetitive at times. IGN gave the game a score of 8.5 and also their Editor's Choice Award.

The series was popular enough to have a movie called Professor Layton and the Eternal Diva made. It has been released in Japan, Singapore, France, Germany, the UK, Spain, America and Canada. It received positive reviews from the first six countries, but has not yet been talked about in reviews in America and Canada. It was released in the UK on the 18th of October, with a full English Dub.[50]

Nintendo Power listed series mascot Professor Layton as their 10th favorite hero, citing his use of brains over brawn.[51]

The series has gone on to be one of the most successful Nintendo DS exclusive series, with the lifetime cumulative sales of Professor Layton games standing at 10 million units sold as of October 2010.[2] Level-5 reported 11.47 million unit sales worldwide for the franchise ahead of the release of Professor Layton and the Miracle Mask in February 2011,[52] and over 13 million copies sold in March 2012.[53] In August 2013, Level-5 reported 15 million unit sales worldwide, and is also the most successful Level-5 series.